Storage or infusion bottles, which are mostly intended for a pharmaceutical fluid that has to be kept sterile, are also referred to as blow-fill-seal bottles, reflecting the process steps that are in immediate succession during a manufacturing process. In the case of these storage or infusion bottles, the fluid is filled into them immediately after the plastic bottle has been blown, to subsequently close this bottle as one piece also at the free mouth end of its bottle neck. In as far as a cap is attached to this storage or infusion bottle, such a cap primarily serves as an attachment point for the required infusion equipment. In preparation for an infusion, the cap, the end wall provided at the free end of the bottle neck, and the intermediate space remaining between this cap and the end wall need to be punctured by the infusion cannula for the fluid to be subsequently extractable, for instance drop by drop, from the bottle via this cannula.
Since a cap, which on its inside has a seal disc, made from a rubber-like material for the purpose of puncturing, is attached to the mouth end of the bottle neck of traditional blow-fill-seal bottles, and since an intermediate space remains between the mouth end of the bottle neck of the traditional blow-fill-seal bottles on the one hand and the cap attached to said mouth end on the other hand, a dead space is created in this intermediate space. Into this dead space, leaking fluid flows along the outside of the cannula during the extraction process. That fluid is not subsequently extractable again from the dead space via the cannula. This leakage not only leads to the sterile fluid not being fully usable, but also, the dosing of any drug is complicated by the residual amount of leaked fluid remaining between mouth end of the bottle neck and cap.
DE 44 25 433 C1 discloses a storage bottle designed to accommodate a medical fluid. The known storage bottle has a closure with a cap, a cup-shaped feature with a relatively small diameter projecting from the end wall of the cap. A separately produced, disc-shaped elastic sealing element is inserted from the inside of the cap into this cup-shaped feature. This sealing element has an annular flange on the circumference at its end facing away from the feature. Once the separately produced sealing element has simply been placed into the cup-shaped feature, the sealing element, by its annular flange, can be welded to the inside of the cap. However, when piercing the sealing element with an infusion needle, there is the risk that, prior to puncturing the end wall closing the bottle neck, the needle tip initially deforms this end wall in such a way that a dead space is created between the bottle and the cap attached to it, resulting in the disadvantages mentioned above with regard to an insufficient emptying of the contents of the bottle and an incorrect dosing of the respective drug.